In recent years, there has been a growing trend toward using minimally invasive surgical techniques to perform heretofore complicated and complex operations. Mininimally invasive techniques have therefore been applied to many procedures, such as gall bladder removal, operations on the reproductive organs, urological operations, and more recently, heart valve repair and replacement as well as by-pass operations. Minimally invasive surgery uses only a small incision through which tools are inserted into the patient, with the tool being manipulated from outside the patient. Video is often used so the surgeon can view the surgical site. Minimally invasive surgery has several advantages over other techniques including: less trauma to the patient, smaller incisions, less post-operative pain, quicker recovery time, shorter time spent in the intensive care unit, as well as other advantages that will occur to those skilled in the art.
The nature of minimally invasive surgery demands several criteria that should be considered for any item used in minimally invasive surgery. This disclosure will focus on fasteners and tools used to place fasteners in a minimally invasive surgical technique. Specifically, this disclosure will focus on fasteners and tools used to place fasteners as well as the techniques for using those tools and fasteners in minimally invasive heart valve replacement surgery. For example, the fastener should be capable of expeditious use, with speed being important for many reasons. However, even though speed is important, the fastener must be capable of reliable and secure placement, since a non-secure fastener can have undesirable results. Still further, any item used for minimally invasive surgery, like any item used for any surgery, should have the confidence of the surgeon. This requires any new item to be usable with techniques and tools that are familiar to the surgeon so he or she need not make large changes in a technique they are already familiar with. It has been observed that surgeons are comfortable in making only incremental changes in technique rather than large scale and sweeping changes in technique. In many minimally invasive procedures, access to the surgical site is of paramount concern. The instruments should be designed to have a minimum bulk and to facilitate action that the surgeon can no longer accomplish with his hands due to restricted access. Since the surgeon will have limited access and visualization of the site, it is important that the tools being used facilitate this procedure as much as possible. In addition, since the access is so limited, methods must be effective. There must be a high probability of success in carrying out these techniques for them to be viable and accepted. As mentioned above, heart valve replacement will be used herein as a specific example of a technique that is adaptable to minimally invasive techniques. Heart valve replacement using minimally invasive techniques is fully discussed in co-pending patent application Ser. No. 08/802,948 filed on Feb. 21, 1997 which is a continuation-in-part of co-pending application Ser. No. 08/606,343, filed on Feb. 23, 1996 by the same inventors. The disclosures of these applications are fully incorporated herein by reference. While heart valve replacement will be used as the best mode, it is understood that the invention disclosed in this application can be used in a myriad of techniques as will occur to those skilled in the art based on the teaching of this disclosure. Accordingly, there is no intention to limit the present disclosure to heart valve replacement. Still further, the terms "fastener" and "staple" will be used herein interchangeably. However, those skilled in the art will understand that the term "fastener" can include other elements and a "staple" is a form of fastener.
Currently, heart valves are installed with double lead sutures with a pledget and needles on the end of each suture lead. Each suture needle is independently placed through the annulus of the tissue and the free leads are brought up outside of the cavity. Pairs of these sutures are then placed circumferentially around the annulus where the old valve has been excised. Once all of the sutures are placed the needles are then passed through the sewing cuff on the prosthetic heart valve. The prosthesis heart valve is then slid down the associated suture into place in the annulus and the knots are tied.
Currently, some companies have been making tools to facilitate suturing of heart valves for minimally invasive procedures. These include modifications of existing needle driver (forceps) technology. The problem is that a long tool needed for the minimally invasive access makes it difficult to manipulate the tools and there might be little time savings realized. Surgeons therefore have had a difficult time replicating their current techniques with minimally invasive devices. For instance, when a surgeon places and drives a needle, the path of motion the needle takes through the patient's tissue is on an arc, with the center of the arc determined roughly by the radius of curvature of the needle. In a minimally invasive surgery procedure, one cannot twist the needle driving forceps in the same path as one does when using the "open procedure" instruments. This is due in part to the limited space. Also, this is due to restricted "inline` viewing which is all one can obtain when viewing down a small and narrow tunnel-like incision used in minimally invasive surgical procedures. In addition, some surgeons may, in some procedures, want control of the number of sutures used and the location of each of those sutures. In other words, the procedure will most likely take longer and require greater surgeon skill than would a standard non-minimally invasive operation. This will hamper the growth of minimally invasive procedures.
Therefore, there is a need for a fastener and tool for placing that fastener that will be readily adopted by surgeons practicing minimally invasive surgery, such as heart valve replacement surgery and by-pass surgery.
Still further, it is very undesirable for a suture to come out of the tissue or the item being anchored to the tissue. This can be a problem in older patients with brittle tissue. Therefore, the stress (force per unit area) placed on the tissue by any device used to anchor another device to the patient should be as low as possible. This can be achieved by either reducing the amount of force applied to the tissue or by increasing the area of force application. The amount of force applied may not be easily reduced. Therefore, there is a need for a fastener that can increase the total area of force application in an anchor situation without unduly sacrificing other advantages.
Still further, suturing patterns can be time consuming, and can be difficult. Anything that can shorten the time of a surgical procedure can be advantageous. Therefore, there is a need for a fastener that can be quickly placed yet will still permit a surgeon to have great control of the suturing process and pattern. The suturing pattern can minimize the time a surgeon spends tying off knots as well.
As can be appreciated, the placement of devices in a minimally invasive manner has visibility problems associated therewith. Since the operation is occurring deep inside a patient, and the surgeon is manipulating tools from outside the patient, visibility as well as ease of manipulation are both important issues that should be considered in designing elements that are to be used in minimally invasive surgery.
Therefore, there is a need for a fastener and a tool for placing that fastener that can be as visible as possible during a minimally invasive surgical procedure, yet will be as easy as possible to place and operate.
Still further, since many patients have variations in size and spacing for the tissue to which a prosthetic device is to be anchored, the surgeon may want to add suture anchors to the anchors that are supplied with the device of the present invention. Therefore, some means should be available to permit a surgeon to customize the anchoring features of the system as needed.